/Engine/Source/Runtime/NetworkReplayStreaming/NetworkReplayStreaming/Public/NetworkReplayStreaming.h
Changes the base directory where Demos are stored. Note, this will always fail for streamers that don't support replays stored on disk. This method should not be called after StartStreaming, or while async operations are pending on a streamer.
EStreamingOperationResult SetDemoPath ( const [FString](API\Runtime\Core\Containers\FString) & DemoPath )